The folks at Gaboogie know there VoIP. One of the issues they face is the call quality issue between all the different access providers. In doing their research they've found that Vonage isn't really cutting the mustard in the quality department.
That's no surprise. Vonage uses the open "Public" internet and has never contended that they do anything to manage the call quality. As more and more people migrate to VoIP, and as business uses VOIP to extend their presence to where their employees are living.
For a long time we've said here that all VoIP isn't created equally. This is one example. It looks like it is becoming the time to really deliver QoS for Vonage or to go home only, and forget the business market once and for all.